The latest data are out on the prevalence of global warming denial among the US public. And they aren't pretty. The new study, from the Yale and George Mason research teams on climate change communication, shows a 7-percentage-point increase in the proportion of Americans who say they do not believe that global warming is happening. And that's just since the spring of 2013. The number is now 23 percent; back at the start of last year, it was 16 percent: